Experimental and CFD Evaluation of a Parallel-Flow Solar Air Heater Featuring a V-Grooved Absorber Incorporating Wire Mesh Layers Within the Downward-Pointing Channels

Abstract

A unique V-grooved solar air collector was assessed experimentally and numerically to improve thermohydraulic performance. Experiments were conducted on the collector in Baghdad, Iraq, from 23 March to 3 April 2025, encompassing a mass airflow rate spanning 0.02 to 0.09 kg/s. The proposed design integrates wire mesh layers solely within the upper triangular channels, while the lower triangular channels remain unobstructed. A novel three-dimensional steady-state CFD model was originally developed for evaluating the thermohydraulic performance of a V-grooved solar air heater with and without wire mesh layers. The coupling between fluid flow and heat transfer models was implemented via the finite element method through the COMSOL Multiphysics program. The developed model for the collector incorporating wire mesh layers was validated experimentally, demonstrating strong agreement, with the greatest recorded root mean square error of 1.3597 °C for the outlet air temperature. The findings indicate that the enhanced collector attains a thermal efficiency enhancement of around 1.5 to 2.5 times relative to the baseline design, depending on operating conditions. The thermal efficiency attained levels up to 80%, whereas the thermohydraulic efficiency surpassed 70% at a moderate mass airflow rate. Despite the increase in pressure drops, the performance remained exceptional owing to the substantial enhancement in heat gain supported by the unique architecture. The results illustrate that the proposed design presents a viable solution for efficient solar air heating and can be adequately incorporated into near-zero-energy buildings.